Tech Smorgasbord Archives - 35

These items are an archive of past Topical Smorgasbord items that have appeared on the RF Cafe homepage. In keeping with the "cafe"
genre, these tidbits of information are truly a smorgasbord of topics. They all pertain to topics that are related to the general engineering
and science theme of RF Cafe. Note: There is also a huge collection of my 'Factoids' (aka 'Kirt's Cogitations') that might interest you as well.

We have all been treated to a seemingly endless
series of headlines
portending rising ocean levels and the ensuing drowning of costal cities due to
melting ice
in the polar regions. This phenomenon ostensibly is brought on by the exponential increase
in carbon emissions from developing third-world countries as well as established first-world
countries in the post World War II era ... or was it post Vietnam, or maybe post Gulf
War? The reference keeps changing, but it definitely began occurring since at least 1990,
right? There is a problem, though. In the early and mid 1970s climate scientists began
warning us of an approaching ...

8/9/2017

MIA: The Other Half of the Antenna and Cable Loss Equation

For some inexplicable reason, it seems that of the
many articles I read dealing with antenna and feedline efficiencies, rarely is the
receive side of the equation addressed. Yes, transmit power is expensive and there is
a legitimate reason to reduce losses when converting power amplifier output to in-the-air
power, especially for DX operations. However, it doesn't do much good to launch the full permissible
1,500 watts PEP and make a contact on the other side of the world if your system cannot receive
a reply because of the excessive line loss and/or mismatch loss between your antenna and your
receiver. Antennas and feedlines are reciprocal elements so if ...

7/26/2017

A Radio Shack Eulogy

Friends, former employees, and fellow
lovers of all things electronic, we are gathered here today to remember and
honor our lifelong friend and enabler of our hobby and passion,
Radio Shack - once a Tandy company, as we are familiar with it. Radio
Shack has lingered in failing health for a decade, all the time keeping a
brave face on its dwindling number of stores. Caretakers attempted a variety
of infusions and transplants in an attempt to save the American stalwart electronics
retailer. Alas, a confluence of poor management ...

6/14/2017

1930
U.S. Census - Do You Own a Radio?

For Mother's Day this year, the kids and I
got Melanie a 23andMe DNA testing kit. She has spent a fair amount of time over
the years researching the family lineage which, in case you care, traces back primarily
to Germany and Switzerland. Along with some of the online ancestry websites, she
searched the U.S. Census database for immigration and early American household information
(number of people, ages, names, occupations, etc.) The entire
1930 Census form consisted of a single page seeking basic information on whether
you own or rent, value of the home, live on a farm or not, color or race, ...

6/9/2017

Heathkit DX-60B Amateur Radio Transmitter Restoration

Long-time RF Cafe visitor and occasional
contributor Gary Steinhour, KF6U, recently sent me a note saying he had acquired
a very used
Heathkit
DX-60B amateur radio transmitter and was in the process of restoring it. Gary's
first transmitter as a freshly minted Ham over 50 years ago was a DX-60, so this
was an effort to satisfy a nostalgic emotional attachment. The project is complete
now, and boy does it look nice! Gary provides a brief account here ...

6/7/2017

Lightning Protection Systems

If you have ever seen the result of a lightning
strike on electronic equipment, then you know how devastating it can be - often
total destruction that includes molten metal. Woe be unto any human operator who
happens to be in contact with it at the time of the strike. Unprotected antennas
are begging for contact. Shortly after leaving a company where I worked on a Tx/Rx
system for a phased array weather radar I got word that the indoor equipment rack
took a major hit because the guy who maintained the site forgot to reconnect a
lightning
rod system cable after moving it during ...

RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB.
Its primary purpose was to provide me with ready access to commonly needed formulas and reference
material while performing my work as an RF system and circuit design engineer. The Internet
was still largely an unknown entity at the time and not much was available in the form of
WYSIWYG ...

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